Field of the Disclosure
The invention relates to fluid separation systems and methods. More particularly, the invention relates to systems and methods for detecting free plasma hemoglobin in plasma separated out of a plasma-containing fluid.
Description of Related Art
Various blood processing systems now make it possible to collect particular blood constituents, instead of whole blood, from a blood source such as, but not limited to, a container of previously collected blood or other living or non-living source. Typically, in such systems, whole blood is drawn from a blood source, the particular blood component or constituent is separated, removed, and collected, and the remaining blood constituents are returned to the blood source. Removing only particular constituents is advantageous when the blood source is a human donor, because potentially less time is needed for the donor's body to return to pre-donation levels, and donations can be made at more frequent intervals than when whole blood is collected. This increases the overall supply of blood constituents, such as plasma and platelets, made available for transfer and/or therapeutic treatment.
Whole blood is typically separated into its constituents (e.g., red cells, platelets, and plasma) through centrifugation, such as in the AMICUS® separator from Fenwal, Inc. of Lake Zurich, Ill., which is an affiliate of Fresenius Kabi AG of Bad Homburg, Germany, or other centrifugal separation devices, or a spinning membrane-type separator, such as the AUTOPHERESIS-C® and AURORA® devices from Fenwal, Inc.
In some of these systems, an optical device is provided for detecting the presence of free plasma hemoglobin in separated blood plasma. Known systems typically include an alert or alarm system that is programmed to generate an alert or alarm when the concentration of free plasma hemoglobin in the plasma exceeds a threshold value. However, experience has shown that the concentration of free plasma hemoglobin in the plasma varies over time, and that a high free plasma hemoglobin concentration at one instant does not necessarily indicate that an undesirable total amount of free plasma hemoglobin is being returned to a donor or patient or blood source. Accordingly, the need remains for a plasma monitoring system that can prevent the return of excess free plasma hemoglobin to a donor or patient or blood source, while eliminating or reducing the number of unnecessary or nuisance alarms or alerts caused by transient elevated free plasma hemoglobin concentration in the separated plasma.